1. Field of the Invention
The present invention relates to an apparatus for inspecting a liquid crystal display (LCD), and more particularly, to an LCD inspection apparatus that is capable of preventing reduction in life span of a backlight unit included in the LCD, and an inspection method using the inspection apparatus.
2. Discussion of the Related Art
In general, an LCD inspection apparatus is able to easily inspect, with the naked eye, whether or not an LCD panel has defects. FIGS. 1 and 2 illustrate such an LCD inspection apparatus according to the related art. As shown in FIGS. 1 and 2, the related art LCD inspection apparatus includes a body 1, an inspection stage 2 arranged at one side of the body 1 to inspect an LCD panel 10 (FIG. 2), and a loading/unloading stage 7 arranged at the other side of the body 1 to load the LCD panel 10 on the inspection stage 2 or to unload the inspected LCD panel 10 from the inspection stage 2. The LCD inspection apparatus also includes a carrier 9 (FIG. 2) mounted to the body 1 such that the carrier 9 is able to laterally move to transfer the LCD panel 10 from the loading/unloading stage 7 to the inspection stage 2, or from the inspection stage 2 to the loading/unloading stage 7.
The inspection stage 2 includes probe units 3, and a worktable 4 that brings the LCD panel 10 into contact with the probe units 3 and also provides light. The worktable 4 includes a polarizing plate 4a and a backlight 4b (FIG. 2). A moving stage 5 is arranged in the rear of the worktable 4, to move the worktable 4 so that the worktable 4 is connected to the probe units 3 in a state of being aligned with the probe units 3.
As shown in FIG. 1, a sub-table 8 is mounted to the loading/unloading stage 7. The sub-table 8 serves to incline the LCD panel 10 transferred from a loader (not shown) of the loading/unloading stage 7 by a predetermined angle (for example, 60°). A microscope 6 is mounted to the body 1 in front of the inspection stage 2 such that the microscope 6 is able to move in vertical and lateral directions. When determining whether the LCD panel 10 has defects during a macroscopic inspection operation for the LCD panel 10, the operator can use the microscope 6 to further precisely identify the defects in the LCD panel 10.
Next, an inspection procedure performed by the related art LCD inspection apparatus will be described as follows.
First, the LCD panel 10 to be inspected is transferred from the loader (not shown) of the loading/unloading stage 7 to the sub-table 8. The sub-table 8 inclines the LCD panel 10 by a predetermined angle while transferring the LCD panel 10 to the carrier 9. Subsequently, the carrier 9 places the LCD panel 10 on the inspection stage 2. Once the LCD panel 10 is seated on the inspection stage 2, the worktable 4 is moved toward the LCD panel 10 by the moving stage 5. Thereafter, the worktable 4 vacuum-chucks the LCD panel 10 so that the LCD panel 10 is fixed on the inspection stage 2, and then connects pads (not shown) of the fixed LCD panel 10 to lead pins (not shown) of the probe units 3, respectively. Thus, when an electrical connection is achieved between the LCD panel 10 and the probe units 3, a predetermined image signal from a pattern generator is input to the LCD panel 10 via the probe units 3. The pattern generator, which is an external image signal input unit, sequentially provides various image patterns. When the LCD panel 10 is illuminated by the backlight 4b, the various image patterns are sequentially displayed on the LCD panel 10. Accordingly, the operator can determine, through the displayed patterns, whether or not the LCD panel 10 has defects.
However, the above-described related art LCD inspection apparatus has various problems. For example, the related art LCD inspection apparatus typically uses a cold fluorescent lamp (CFL) or a cold cathode fluorescent lamp (CCFL) as the backlight 4b. During the defect inspection of the LCD panel according to the related art, the backlight 4b is frequently turned-on/off, thereby reducing the life span thereof and causing an increase in the costs. Accordingly, it is necessary to provide a new configuration capable of minimizing the operations of turning-on/off the backlight 4b. Further, the related art LCD inspection apparatus inspects the LCD panel 10 depending on the naked eye of the operator, thereby easily causing an inaccurate inspection due to the operator's carelessness. Moreover, it becomes time-consuming for one operator to completely inspect the LCD panel 10 in view of its increasing size. In addition, as shown in FIG. 3, when fine dust D is attached to the surfaces of upper and lower substrates 11 of the LCD panel 10, even though the fine dust D is not a defect in the LCD panel 10, it is practically very difficult for the operator to distinguish a point defect PD in LCD panel 10 from the fine dust D. As a result, even non-defective products may be determined as being defective, thereby degrading yield and increasing manufacturing costs.